Off-by-one error in the rfc822_output_char function in the RFC822BUFFER routines in the University of Washington (UW) c-client library, as used by the UW IMAP toolkit before imap-2007e and other applications, allows context-dependent attackers to cause a denial of service (crash) via an e-mail message that triggers a buffer overflow.

The default configuration of University of Washington IMAP daemon (wu-imapd), when running on a system that does not allow shell access, allows a local user with a valid IMAP account to read arbitrary files as that user.